New imaging technology promises to change HDTV equation

June 20, 2006

The New York Post recently ran a story about a Canadian company that may shake up the consumer market for HDTVs with a new display technology that can deliver full 1080p display at a fraction of the cost of other flat panel displays.

The company has set up a pilot production line in Toronto to produce prototypes and engineering samples and is seeking partners to bring HDTVs to market using TDEL technology.

HD Technology Update spoke with iFire Technology vice president of product planning Don Carkner to learn more about how TDEL technology works and its potential impact on what type of HDTVs consumers watch in the future.

HD Technology Update: What can you tell me about how the thick dielectric electroluminescent technology (TDEL) works?

Don Carkner: In the simplest terms, electroluminescent technology is a stack of solid films where we apply a voltage across the structure, and one of the films emits light.

It’s a stack of solid material. We start with a glass substrate that’s the same as plasma glass. On that, we screen print a set of row electrodes which form the back electrodes of the display, and then we screen print an insulating layer that we call the thick dielectric.

This layer is a bit unique because its thickness is around 10 microns, and this allows us to manufacture in a relatively simple clean room environment, because very small particles, like 1 micron in size, will not create defects in this display. That allows us to scale it up pretty easily and also simplifies the manufacturing process. Screen printing is a fairly well known industrial process. It’s not like semiconductor processing. It’s more like PC board making.

Once the thick film is done, then the next step is to put on a phosphor material, which we do by sputtering, and the material we’ve developed is a blue phosphor. We actually only use a blue phosphor to generate light, and I’ll explain how we make a full color display in a second.

The thick film screen-printed insulating layer and the blue film don’t have any pattern in them. They’re just simple sheets, so they don’t have to be aligned with anything. On top of the phosphor, we put an ITO layer to form the top electrode. We need to have an electrode that is on the back and the front to form the matrix whereby we address the display. The ITO is also sputtered, and then patterned into columns perpendicular to the rows that are on the back. The two sets of electrodes form the matrix that defines the pixels. We use a passive matrix type scheme, so we don’t have a TFT. We don’t have an active matrix array. We don’t need that.

And so basically, once the ITO is done, we have a display that works. We can test it, we can do rework on it if that’s necessary, but it’s only blue. In order to turn it into a full color display, after the ITO, we screen print on color conversion materials, which are essentially fluorescent phosphors that are excited by the blue light from the blue phosphor, and they re-emit red or green light, depending on the material. So over the red columns, we print a red stripe and over the green columns we print a green stripe, and so then we have a red, green, blue display.

The only thing that remains is to attach a pane of window glass that doesn’t have any process on it over the top, to protect it from the environment.

So overall, the whole structure is quite simple. There isn’t much alignment. Really the only alignment requirement is between the color conversion material and the ITO columns. The rest of it is just basically rough physical alignment. And the use of the thick film layer for the insulating layer allows us to operate in a simpler clean room environment. It’s also a fairly short process. Not many steps, relatively simple tools, and the facility required is quite simple. That’s the advantage that we bring in terms of cost of the technology. It’s low capital cost to manufacture, and the module cost can also be quite low.

In operation, this technology is also pretty simple. We select each row one at a time by applying a voltage onto the row driver and then while that select voltage is being held there, we apply the voltage on each of the columns in order to get the right light output from each pixel.

The luminance response for this type of technology is proportional to the voltage you apply. It’s an analog gray scale type of technology, just like CRT, and unlike plasma, which is a digital technology.

That also has an advantage. The way the video is produced is very similar to the way it works on a CRT, so you don’t have to do a lot of video manipulations in order to get it to look good.

DC:In TDEL technology there is no liquid, gas or vacuum — just solid state materials. It’s surface emissive, it has a very wide viewing angle, it has a very fast response time, so it basically looks like a traditional CRT-based television.

So compared with an LCD, we would expect to have better viewing angle, faster response time and also better dark room contrast because we don’t have a big backlight in the back.

Compared to a plasma, our grayscale is better because it’s analog. In the case of a plasma, the pixels are only either on or off, kind of like a fluorescent light. In order to make grayscale on a plasma you have to turn the pixels on and off quickly to sort of time average the grayscale into what you see. Where in our case, we just adjust the voltage on a pixel and that adjusts the light output. We don’t have any of the false contours or sort of shimmering or dithering artifacts that are sometime on plasma. And the other difference from plasma is we can do very small pixels if we want to. Typically smaller plasma displays, like 30 to 40 inch displays, are not made as native high definition. They don’t have 1280 columns. We can do that. We can do either 1280 by 720 columns or 1920 by 1080 from about 30 inches up to about 50 inches.

Those would be the two major differences in terms of optical quality. As for rear projection, it depends on each of the different flavors of rear projection. Each has slightly different characteristics. Versus a DLP, they have an on and off characteristic like a plasma so they have to switch on and off quickly so fast moving images would tend to have color breakup. In our case, we wouldn’t have that. And of course there’s the physical difference.

TDEL can be a truly hang-on-the-wall technology, where all the projection technologies have a certain depth.

The main advantages we attribute to our technology are in the categories of package, performance and price. We’ve talked about performance. In the package category of things, because there is no backlight and because the drive electronics are relatively simple, we can make a display that’s very thin and very light. We’ve done a little conceptual TV set design with our joint development partner Sanyo, and we believe a 37in TV set could be made that’s about 2cm, or less than 1in thick, and would weigh about 10kg or about 22lbs.

That would be quite different than existing LCDs or plasma, which are more like 10cm thick and maybe 25kg for LCD and for plasma about 40kg. We think that thinness and lightness leads to some interesting industrial design possibilities. You could imagine being able to hang it on a wall, a lot like a picture, without having to buy a special bracket or reinforce the wall.

HDTU: What is the significance of the Color By Blue and how does it work?

DC: The significance of it is that it simplifies the manufacturing process while at the same time improving video quality. In the past we made displays with three emitters, red, green and blue primary phosphors. And we were able to get quite good performance but we found that it was challenging to be able to perfectly match the grayscale for all three colors everywhere on the panel.

It turns out that if you look at all the different technologies, CRT, plasma or LCD, they all have a way of separating the light emission or the luminance-generating characteristic from the color-generating characteristic. A CRT has a gun and then it’s got phosphors. An LCD has backlighting and filters and plasma has plasma together with phosphors that are excited the plasma. In each case, that allows them to basically decouple color generation from the luminance generation.

Your eye is not as sensitive to variations in luminance as it is to changes in color. So when we went to the color by blue, the primary reason to do it was actually for the simplicity. It enabled us to get all of the light emissions out of one phosphor material, so we didn’t have to do any photolithography or patterning work on the phosphor layers.

But it had this additional benefit of bringing this same feature where the luminance emission and color selection are separated. That means the blue phosphor, which is responsible for generating the luminance, is allowed is a lot more tolerance for variation, because you’re eye’s less sensitive to luminance changes. And then the conversion phosphor structure — the Color By Blue structure — is responsible for generating color. And because of the way that it’s made, basically the physical geometry of it selects the color that you see. So we are able, with this structure, to get an extremely uniform display, even in the prototypes we are making now.

The CBB was a big step forward, both in simplifying the structure and therefore improving the economics of the manufacturing and also in the video quality. Everything that we make now is based on this concept.

HDTU: Recent remarks from market researcher iSuppli contend LCDs are positioned to dominate display, and there’s nothing on the horizon to challenge that technology for dominance. Can your technology be a competitor to LCD and plasma?

DC: We look at the market for our technology to be in the 30in to 50in range, which is at the high end of LCD’s mainstream and at the lower end of PDP’s mainstream. When we do our cost modeling versus the forecast, normally we look at the module price forecasts more so than the retail because the retail entails a lot of other margins for the distributor and margins for the retailer. But just looking at the module price forecast, for a 37in LCD it’s roughly $650, and the forecasts show the price continuing to drop down to the range of $350 to $400 in the 2009-2010 timeframe.

With our technology, due to the simplicity and low capital cost, we are very confident in getting well under $300 for a module cost. That’s in the future, also comparing against the future forecast for LCD and plasma.

We see the technology as having two main advantages in price. One is the capital cost, which is really pertinent for manufacturers if they have to make a decision to add capacity. If they’re looking at a LCD line for Gen 6, it could be something like $1.6 billion in capital, whereas for us it would be something like $600 million. So something on the order of one-third the capital cost. Then the second part of it is the module cost.

According to our cost calculations versus forecast module cost prices of LCD, we appear to have a significant and sustainable advantage. So we think that’s pretty compelling, especially given that in the past few months, there have been quite a few questions about the profitability of even Tier 1 LCD manufacturers. It just seems that a lot of capacity has been built and the market hasn’t materialized quite as quickly as expected.

So, by going with a technology like TDEL instead, the combination of not having to risk as much capital and in addition, having the opportunity to be more profitable as time goes on, is pretty compelling.

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